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Oakley RB, Gemechu G, Gebregiorgis A, Alemu A, Zinsstag J, Paris DH, Tschopp R. Seroprevalence and risk factors for Q fever and Rift Valley fever in pastoralists and their livestock in Afar, Ethiopia: A One Health approach. PLoS Negl Trop Dis 2024; 18:e0012392. [PMID: 39178328 PMCID: PMC11376510 DOI: 10.1371/journal.pntd.0012392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 09/05/2024] [Accepted: 07/22/2024] [Indexed: 08/25/2024] Open
Abstract
BACKGROUND Coxiella burnetii, the causative agent of Q fever, and Rift Valley fever virus are two under-researched zoonotic pathogens in Ethiopia. Potential outbreaks of these diseases, in light of the high dependency of nomadic pastoralists on their livestock, poses a risk to both human and animal health in addition to risking the pastoralists livelihoods. Our study aimed to determine the seroprevalence and associated risk factors for Q fever and Rift Valley fever in pastoral communities in the Afar region of north-eastern Ethiopia. METHODOLOGY/PRINCIPAL FINDINGS This cross-sectional study screened pastoralists (n = 323) and their livestock (n = 1377) for IgG antibodies to Coxiella burnetii and Rift Valley fever virus. A seroprevalence for Q fever of 25.0% (95%CI 18.6-32.6) was found in pastoralists and 34.3% (95%CI 27.9-41.3) in livestock overall; with 51.9% in goats (95%CI 44.9-58.8), 39.9% in sheep (95%CI 24.6-51.2), 16.3% in camels (95%CI 10.4-24.6) and 8.8% in cattle (95%CI 5.0-15.0). For Rift Valley fever the seroprevalence in pastoralists was 6.1% (95%CI 3.3-11.0) and 3.9% (95%CI 2.6-5.7) in livestock overall; cattle had the highest seroprevalence (8.3%, 95%CI 3.3-19.2), followed by goats (2.7%; 95%CI 1.4-5.1), sheep (2.5%; 95%CI 1.0-5.9) and camels (1.8%; 95%CI 0.4-6.9). Human Q fever seropositivity was found to be associated with goat abortions (OR = 2.11, 95%CI 1.18-3.78, p = 0.011), while Rift Valley fever seropositivity in livestock was found to be associated with cattle abortions (OR = 2.52, 95%CI 1.05-6.08, p = 0.039). CONCLUSIONS/SIGNIFICANCE This study provides evidence for a notable exposure to both Q fever and Rift Valley fever in pastoralists and livestock in Afar. The outbreak potential of these pathogens warrants ongoing integrated human and animal surveillance requiring close collaboration of the human and animal health sectors with community representatives following a One Health approach.
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Affiliation(s)
- Regina Bina Oakley
- Department of Medicine, Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Gizachew Gemechu
- One Health Division, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | | | - Ayinalem Alemu
- One Health Division, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
| | - Jakob Zinsstag
- University of Basel, Basel, Switzerland
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Allschwil, Switzerland
| | - Daniel Henry Paris
- Department of Medicine, Swiss Tropical and Public Health Institute, Allschwil, Switzerland
- University of Basel, Basel, Switzerland
| | - Rea Tschopp
- University of Basel, Basel, Switzerland
- One Health Division, Armauer Hansen Research Institute, Addis Ababa, Ethiopia
- Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Allschwil, Switzerland
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Alem F, Brahms A, Tarasaki K, Omole S, Kehn-Hall K, Schmaljohn CS, Bavari S, Makino S, Hakami RM. HSP90 is part of a protein complex with the L polymerase of Rift Valley fever phlebovirus and prevents its degradation by the proteasome during the viral genome replication/transcription stage. Front Cell Infect Microbiol 2024; 14:1331755. [PMID: 38800833 PMCID: PMC11127626 DOI: 10.3389/fcimb.2024.1331755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 04/08/2024] [Indexed: 05/29/2024] Open
Abstract
The mosquito-borne Rift Valley fever virus (RVFV) from the Phenuiviridae family is a single-stranded RNA virus that causes the re-emerging zoonotic disease Rift Valley fever (RVF). Classified as a Category A agent by the NIH, RVFV infection can cause debilitating disease or death in humans and lead to devastating economic impacts by causing abortion storms in pregnant cattle. In a previous study, we showed that the host chaperone protein HSP90 is an RVFV-associated host factor that plays a critical role post viral entry, during the active phase of viral genome replication/transcription. In this study, we have elucidated the molecular mechanisms behind the regulatory effect of HSP90 during infection with RVFV. Our results demonstrate that during the early infection phase, host HSP90 associates with the viral RNA-dependent RNA polymerase (L protein) and prevents its degradation through the proteasome, resulting in increased viral replication.
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Affiliation(s)
- Farhang Alem
- School of Systems Biology, George Mason University, Manassas, VA, United States
| | - Ashwini Brahms
- School of Systems Biology, George Mason University, Manassas, VA, United States
| | - Kaori Tarasaki
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX, United States
| | - Samson Omole
- School of Systems Biology, George Mason University, Manassas, VA, United States
| | - Kylene Kehn-Hall
- School of Systems Biology, George Mason University, Manassas, VA, United States
| | - Connie S. Schmaljohn
- Integrated Research Facility at Fort Detrick, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD, United States
| | - Sina Bavari
- Tonix Pharmaceuticals, Frederick, MD, United States
| | - Shinji Makino
- Department of Microbiology and Immunology, The University of Texas Medical Branch, Galveston, TX, United States
| | - Ramin M. Hakami
- School of Systems Biology, George Mason University, Manassas, VA, United States
- Center for Infectious Disease Research, George Mason University, Manassas, VA, United States
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Muturi M, Mwatondo A, Nijhof AM, Akoko J, Nyamota R, Makori A, Nyamai M, Nthiwa D, Wambua L, Roesel K, Thumbi SM, Bett B. Ecological and subject-level drivers of interepidemic Rift Valley fever virus exposure in humans and livestock in Northern Kenya. Sci Rep 2023; 13:15342. [PMID: 37714941 PMCID: PMC10504342 DOI: 10.1038/s41598-023-42596-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 09/12/2023] [Indexed: 09/17/2023] Open
Abstract
Nearly a century after the first reports of Rift Valley fever (RVF) were documented in Kenya, questions on the transmission dynamics of the disease remain. Specifically, data on viral maintenance in the quiescent years between epidemics is limited. We implemented a cross-sectional study in northern Kenya to determine the seroprevalence, risk factors, and ecological predictors of RVF in humans and livestock during an interepidemic period. Six hundred seventy-six human and 1,864 livestock samples were screened for anti-RVF Immunoglobulin G (IgG). Out of the 1,864 livestock samples tested for IgG, a subset of 1,103 samples was randomly selected for additional testing to detect the presence of anti-RVFV Immunoglobulin M (IgM). The anti-RVF virus (RVFV) IgG seropositivity in livestock and humans was 21.7% and 28.4%, respectively. RVFV IgM was detected in 0.4% of the livestock samples. Participation in the slaughter of livestock and age were positively associated with RVFV exposure in humans, while age was a significant factor in livestock. We detected significant interaction between rainfall and elevation's influence on livestock seropositivity, while in humans, elevation was negatively associated with RVF virus exposure. The linear increase of human and livestock exposure with age suggests an endemic transmission cycle, further corroborated by the detection of IgM antibodies in livestock.
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Affiliation(s)
- Mathew Muturi
- Department of Veterinary Medicine, Dahlem Research School of Biomedical Sciences (DRS), Freie Universität Berlin, Berlin, Germany.
- International Livestock Research Institute, Nairobi, Kenya.
- Kenya Zoonotic Disease Unit, Ministry of Health and Ministry of Agriculture, Nairobi, Kenya.
- Center for Epidemiological Modelling and Analysis-University of Nairobi, Nairobi, Kenya.
| | - Athman Mwatondo
- International Livestock Research Institute, Nairobi, Kenya
- Kenya Zoonotic Disease Unit, Ministry of Health and Ministry of Agriculture, Nairobi, Kenya
- Department of Medical Microbiology and Immunology, University of Nairobi, Nairobi, Kenya
| | - Ard M Nijhof
- Veterinary Centre for Resistance Research, Freie Universität Berlin, Berlin, Germany
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Univesität Berlin, Berlin, Germany
| | - James Akoko
- International Livestock Research Institute, Nairobi, Kenya
| | | | - Anita Makori
- Center for Epidemiological Modelling and Analysis-University of Nairobi, Nairobi, Kenya
- Paul G Allen School for Global Health, Washington State University, Pullman, WA, USA
| | - Mutono Nyamai
- Center for Epidemiological Modelling and Analysis-University of Nairobi, Nairobi, Kenya
- Paul G Allen School for Global Health, Washington State University, Pullman, WA, USA
| | - Daniel Nthiwa
- Department of Biological Sciences, University of Embu, Embu, Kenya
| | - Lilian Wambua
- International Livestock Research Institute, Nairobi, Kenya
| | | | - S M Thumbi
- Center for Epidemiological Modelling and Analysis-University of Nairobi, Nairobi, Kenya
- Paul G Allen School for Global Health, Washington State University, Pullman, WA, USA
- Institute for Immunology and Infection Research, University of Edinburgh, Edinburgh, Scotland, UK
| | - Bernard Bett
- International Livestock Research Institute, Nairobi, Kenya
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Ebogo‐Belobo JT, Kenmoe S, Abanda NN, Bowo‐Ngandji A, Mbaga DS, Magoudjou‐Pekam JN, Kame‐Ngasse GI, Tchatchouang S, Menkem EZ, Okobalemba EA, Noura EA, Meta‐Djomsi D, Maïdadi‐Foudi M, Kenfack‐Zanguim J, Kenfack‐Momo R, Kengne‐Nde C, Esemu SN, Mbacham WF, Sadeuh‐Mba SA, Ndip L, Njouom R. Contemporary epidemiological data of Rift Valley fever virus in humans, mosquitoes and other animal species in Africa: A systematic review and meta-analysis. Vet Med Sci 2023; 9:2309-2328. [PMID: 37548116 PMCID: PMC10508527 DOI: 10.1002/vms3.1238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 03/29/2023] [Accepted: 07/21/2023] [Indexed: 08/08/2023] Open
Abstract
Rift Valley fever (RVF) is a severe zoonotic mosquito-borne disease that represents an important threat to human and animal health, with major public health and socioeconomic impacts. This disease is endemic throughout many African countries and the Arabian Peninsula. This systematic review with meta-analysis was conducted to determine the RVF prevalence in humans, mosquitoes and other animal species in Africa. The review also provides contemporary data on RVF case fatality rate (CFR) in humans. In this systematic review with meta-analysis, a comprehensive literature search was conducted on the PubMed, Embase, Web of Science and Global Index Medicus databases from January 2000 to June 2022 to identify relevant studies. Pooled CFR and prevalence estimates were calculated using the random-effects model. Subgroup analysis and sensitivity analysis were performed, and the I2 -statistic was used to investigate a potential source of heterogeneity. A total of 205 articles were included in the final analysis. The overall RVF CFR in humans was found to be 27.5% [95% CI = 8.0-52.5]. The overall pooled prevalence was 7.8% [95% CI = 6.2-9.6] in humans and 9.3% [95% CI = 8.1-10.6] in animals, respectively. The RVF prevalence in individual mosquitoes ranged from 0.0% to 25%. Subgroup analysis showed substantial heterogeneity with respect to geographical regions and human categories. The study shows that there is a correspondingly similar prevalence of RVF in human and animals; however, human CFR is much higher than the observed prevalence. The lack of a surveillance programme and the fact that this virus has subclinical circulation in animals and humans could explain these observations. The implementation of a One Health approach for RVF surveillance and control would be of great interest for human and animal health.
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Affiliation(s)
- Jean Thierry Ebogo‐Belobo
- Centre for Research on Health and Priority PathologiesInstitute of Medical Research and Medicinal Plants StudiesYaoundeCameroon
- Department of BiochemistryFaculty of SciencesThe University of Yaounde IYaoundéCameroon
| | - Sebastien Kenmoe
- Department of Microbiology and ParasitologyUniversity of BueaBueaCameroon
| | - Ngu Njei Abanda
- Virology DepartmentCentre Pasteur of CameroonYaoundéCameroon
| | - Arnol Bowo‐Ngandji
- Department of MicrobiologyFaculty of SciencesThe University of Yaounde IYaoundéCameroon
| | - Donatien Serge Mbaga
- Department of MicrobiologyFaculty of SciencesThe University of Yaounde IYaoundéCameroon
| | | | - Ginette Irma Kame‐Ngasse
- Centre for Research on Health and Priority PathologiesInstitute of Medical Research and Medicinal Plants StudiesYaoundeCameroon
| | | | | | | | - Efietngab Atembeh Noura
- Centre for Research on Health and Priority PathologiesInstitute of Medical Research and Medicinal Plants StudiesYaoundeCameroon
| | - Dowbiss Meta‐Djomsi
- Research Centre on Emerging and Re‐Emerging DiseasesInstitute of Medical Research and Medicinal Plants StudiesYaoundeCameroon
| | - Martin Maïdadi‐Foudi
- Research Centre on Emerging and Re‐Emerging DiseasesInstitute of Medical Research and Medicinal Plants StudiesYaoundeCameroon
| | | | - Raoul Kenfack‐Momo
- Department of BiochemistryFaculty of SciencesThe University of Yaounde IYaoundéCameroon
| | - Cyprien Kengne‐Nde
- Epidemiological Surveillance, Evaluation and Research UnitNational AIDS Control CommitteeYaoundéCameroon
| | | | - Wilfred Fon Mbacham
- Department of BiochemistryFaculty of SciencesThe University of Yaounde IYaoundéCameroon
| | - Serge Alain Sadeuh‐Mba
- Virology DepartmentCentre Pasteur of CameroonYaoundéCameroon
- Maryland Department of AgricultureSalisbury Animal Health LaboratorySalisburyMarylandUSA
| | - Lucy Ndip
- Department of Microbiology and ParasitologyUniversity of BueaBueaCameroon
| | - Richard Njouom
- Virology DepartmentCentre Pasteur of CameroonYaoundéCameroon
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Johnson SAM, Asmah R, Awuni JA, Tasiame W, Mensah GI, Paweska JT, Weyer J, Hellferscee O, Thompson PN. Evidence of Rift Valley Fever Virus Circulation in Livestock and Herders in Southern Ghana. Viruses 2023; 15:1346. [PMID: 37376647 DOI: 10.3390/v15061346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 06/05/2023] [Accepted: 06/07/2023] [Indexed: 06/29/2023] Open
Abstract
Rift Valley fever (RVF) is a re-emerging zoonotic disease of domestic ruminants and humans. While neighbouring countries have reported outbreaks of RVF, Ghana has not yet identified any cases. The aim of this study was to determine whether RVF virus (RVFV) was circulating in livestock and herders in the southern part of Ghana, to estimate its seroprevalence, and to identify associated risk factors. The study surveyed 165 livestock farms randomly selected from two districts in southern Ghana. Serum samples of 253 goats, 246 sheep, 220 cattle, and 157 herdsmen were tested to detect IgG and IgM antibodies against RVFV. The overall seroprevalence of anti-RVF antibodies in livestock was 13.1% and 30.9% of farms had RVFV seropositive animals. The species-specific prevalence was 24.1% in cattle, 8.5% in sheep, and 7.9% in goats. A RVFV IgG seroprevalence of 17.8% was found among the ruminant herders, with 8.3% of all herders being IgM positive. RVFV was shown, for the first time, to have been circulating in southern Ghana, with evidence of a recent outbreak in Kwahu East; however, it was clinically undetected despite significant recent human exposure. A One Health approach is recommended to better understand RVF epidemiology and socio-economic impact in Ghana.
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Affiliation(s)
- Sherry Ama Mawuko Johnson
- Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa
- School of Veterinary Medicine, University of Ghana, Legon, Accra 00233, Ghana
| | - Richard Asmah
- School of Biomedical & Allied Health Sciences, University of Ghana, Accra 00233, Ghana
| | - Joseph Adongo Awuni
- Accra Veterinary Laboratory, Ministry of Food and Agriculture, Accra P.O. Box M161, Ghana
| | - William Tasiame
- School of Veterinary Medicine, Kwame Nkrumah University of Science and Technology, Kumasi 00233, Ghana
| | - Gloria Ivy Mensah
- Noguchi Memorial Institute for Medical Research, University of Ghana, Accra 00233, Ghana
| | - Janusz T Paweska
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Sandringham, Johannesburg 2192, South Africa
- Department of Medical Virology, Faculty of Health Sciences, University of Pretoria, Pretoria 0002, South Africa
| | - Jacqueline Weyer
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Sandringham, Johannesburg 2192, South Africa
- Department of Medical Virology, Faculty of Health Sciences, University of Pretoria, Pretoria 0002, South Africa
| | - Orienka Hellferscee
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Sandringham, Johannesburg 2192, South Africa
- Department of Medical Virology, Faculty of Health Sciences, University of Witwatersrand, Johannesburg 2050, South Africa
| | - Peter N Thompson
- Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort 0110, South Africa
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Kainga H, Phonera MC, Chatanga E, Kallu SA, Mpundu P, Samutela M, Chambaro HM, Kajihara M, Shempela DM, Sikalima J, Muleya W, Shawa M, Chulu J, Njunga G, Simuunza M, Takada A, Sawa H, Simulundu E, Saasa N. Seroprevalence and Associated Risk Factors of Rift Valley Fever in Livestock from Three Ecological Zones of Malawi. Pathogens 2022; 11:1349. [PMID: 36422600 PMCID: PMC9698272 DOI: 10.3390/pathogens11111349] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 11/04/2022] [Accepted: 11/10/2022] [Indexed: 09/17/2023] Open
Abstract
The epidemiology of Rift Valley fever (RVF) is poorly understood in Malawi. Here, a cross-sectional study was conducted (March-June 2020) to investigate the seroprevalence and potential risk factors of RVF virus (RVFV) in cattle, goats, and sheep in three ecological zones of Malawi. A total of 1523 serum samples were tested for anti-RVFV IgG and IgM antibodies by ELISA. Additionally, a questionnaire survey was used to assess potential RVF risk factors. The overall seroprevalence was 17.14% (261/1523; 95% CI = 15.33-19.11) for individual livestock and 33.24% (120/361; 95% CI = 28.18-38.11) for the livestock herd. Seroprevalence was significantly high in sheep (25.68%, 95% CI = 19.31-33.26) compared with cattle (21.35%, 95% CI = 18.74-24.22) and goats (7.72%, 95% CI = 5.72-10.34), (p = 0.047). At the individual livestock level, the risk was elevated in female livestock (OR: 1.74, 95% CI = 1.08-12.82) (p = 0.016), while at the herd level, areas receiving approximately 1001-1500 mm of rainfall (OR: 2.47, 95% CI = 1.14-5.37) (p = 0.022), areas of rainfall amount greater than approximately 1600 mm (OR: 2.239, 95% CI = 1.07-8.82) (p = 0.023), and mixed species herds (OR: 10.410, 95% CI = 3.04-35.59) (p = 0.001), were significant risk factors. The detection of IgM antibodies confirmed active circulation of RVFV in Malawi. Therefore, monitoring of RVF in animals, humans, and vectors using a "One Health" approach, along with community sensitization among the high-risk populations, could help mitigate the threat posed by this zoonotic disease in Malawi.
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Affiliation(s)
- Henson Kainga
- Department of Veterinary Epidemiology and Public Health, Faculty of Veterinary Medicine, Lilongwe University of Agriculture and Natural Resources, Lilongwe 207203, Malawi
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia
| | - Marvin Collen Phonera
- Department of Animal Health and Livestock Development, Ministry of Agriculture, Lilongwe 207203, Malawi
| | - Elisha Chatanga
- Department of Veterinary Pathobiology, Faculty of Veterinary Medicine, Lilongwe University of Agriculture and Natural Resources, Lilongwe 207203, Malawi
| | - Simegnew Adugna Kallu
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia
- College of Veterinary Medicine, Haramaya University, Dire Dawa P.O. Box 138, Ethiopia
| | - Prudence Mpundu
- Department of Environmental and Occupational Health, Levy Mwanawasa Medical University, Lusaka 33991, Zambia
| | - Mulemba Samutela
- Department of Paraclinical Studies, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia
- Department of Biomedical Sciences, School of Health Sciences, University of Zambia, Lusaka 10101, Zambia
| | - Herman Moses Chambaro
- Virology Unit, Central Veterinary Research Institute (CVRI), Ministry of Fisheries and Livestock, Lusaka 10101, Zambia
| | - Masahiro Kajihara
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia
- Division of Global Epidemiology, International Institute for Zoonosis Control, Hokkaido University, Sapporo 001-0020, Japan
| | | | - Jay Sikalima
- Churches Health Association of Zambia, Lusaka 10101, Zambia
| | - Walter Muleya
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia
| | - Misheck Shawa
- Division of Collaboration and Education, International Institute for Zoonosis Control, Hokkaido University, Sapporo 001-0020, Japan
| | - Julius Chulu
- Department of Animal Health and Livestock Development, Ministry of Agriculture, Lilongwe 207203, Malawi
| | - Gilson Njunga
- Department of Animal Health and Livestock Development, Ministry of Agriculture, Lilongwe 207203, Malawi
| | - Martin Simuunza
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia
| | - Ayato Takada
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia
- Division of Collaboration and Education, International Institute for Zoonosis Control, Hokkaido University, Sapporo 001-0020, Japan
| | - Hirofumi Sawa
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia
- Japan Division of International Research Promotion, International Institute for Zoonosis Control, Hokkaido University, Sapporo 001-0020, Japan
- Japan Global Virus Network, Baltimore, ML 21201, USA
- One Health Research Center, Hokkaido University, Sapporo 001-0020, Japan
| | - Edgar Simulundu
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia
- Macha Research Trust, Choma 20100, Zambia
| | - Ngonda Saasa
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia
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7
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de Glanville WA, Nyarobi JM, Kibona T, Halliday JEB, Thomas KM, Allan KJ, Johnson PCD, Davis A, Lankester F, Claxton JR, Rostal MK, Carter RW, de Jong RMF, Rubach MP, Crump JA, Mmbaga BT, Nyasebwa OM, Swai ES, Willett B, Cleaveland S. Inter-epidemic Rift Valley fever virus infection incidence and risks for zoonotic spillover in northern Tanzania. PLoS Negl Trop Dis 2022; 16:e0010871. [PMID: 36306281 PMCID: PMC9665400 DOI: 10.1371/journal.pntd.0010871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 11/15/2022] [Accepted: 10/06/2022] [Indexed: 11/06/2022] Open
Abstract
Rift Valley fever virus (RVFV) is a mosquito-borne pathogen that has caused epidemics involving people and animals across Africa and the Arabian Peninsula. A number of studies have found evidence for the circulation of RVFV among livestock between these epidemics but the population-level incidence of infection during this inter-epidemic period (IEP) is rarely reported. General force of infection (FOI) models were applied to age-adjusted cross-sectional serological data to reconstruct the annual FOI and population-level incidence of RVFV infection among cattle, goats, and sheep in northern Tanzania from 2009 through 2015, a period without reported Rift Valley fever (RVF) cases in people or animals. To evaluate the potential for zoonotic RVFV spillover during this period, the relationship between village-level livestock RVFV FOI and human RVFV seropositivity was quantified using multi-level logistic regression. The predicted average annual incidence was 72 (95% Credible Interval [CrI] 63, 81) RVFV infections per 10,000 animals and 96 (95% CrI 81, 113), 79 (95% CrI 62, 98), and 39 (95% CrI 28, 52) per 10,000 cattle, sheep, and goats, respectively. There was variation in transmission intensity between study villages, with the highest estimated village-level FOI 2.49% (95% CrI 1.89, 3.23) and the lowest 0.12% (95% CrI 0.02, 0.43). The human RVFV seroprevalence was 8.2% (95% Confidence Interval 6.2, 10.9). Human seropositivity was strongly associated with the village-level FOI in livestock, with the odds of seropositivity in an individual person increasing by around 1.2 times (95% CrI 1.1, 1.3) for each additional annual RVFV seroconversion per 1,000 animals. A history of raw milk consumption was also positively associated with human seropositivity. RVFV has circulated at apparently low levels among livestock in northern Tanzania in the period since the last reported epidemic. Although our data do not allow us to confirm human RVFV infections during the IEP, a strong association between human seropositivity and the FOI in cattle, goats, and sheep supports the hypothesis that RVFV circulation among livestock during the IEP poses a risk for undetected zoonotic spillover in northern Tanzania. We provide further evidence for the likely role of raw milk consumption in RVFV transmission from animals to people.
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Affiliation(s)
- William A. de Glanville
- School of Biodiversity, One Health, and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- University of Global Health Equity, Kigali, Rwanda
- * E-mail: (WAdG); (SC)
| | - James M. Nyarobi
- School of Biodiversity, One Health, and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
| | - Tito Kibona
- Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
| | - Jo E. B. Halliday
- School of Biodiversity, One Health, and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Kate M. Thomas
- Centre for International Health, University of Otago, Dunedin, New Zealand
- Kilimanjaro Clinical Research Institute, Moshi, United Republic of Tanzania
| | - Kathryn J. Allan
- School of Biodiversity, One Health, and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Paul C. D. Johnson
- School of Biodiversity, One Health, and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Alicia Davis
- School of Social and Political Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Felix Lankester
- Paul G. Allen School for Global Health, Washington State University, Pullman, Washington, United States of America
- Global Animal Health Tanzania, Arusha, Tanzania
| | - John R. Claxton
- School of Biodiversity, One Health, and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Melinda K. Rostal
- School of Biodiversity, One Health, and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- EcoHealth Alliance, New York, New York, United States of America
| | - Ryan W. Carter
- School of Biodiversity, One Health, and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Rosanne M. F. de Jong
- School of Biodiversity, One Health, and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Matthew P. Rubach
- Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina, United States of America
- Duke Global Health Institute, Duke University, Durham, North Carolina, United States of America
- Programme in Emerging Infectious Diseases, Duke-National University of Singapore, Singapore
| | - John A. Crump
- Centre for International Health, University of Otago, Dunedin, New Zealand
- Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, North Carolina, United States of America
- Duke Global Health Institute, Duke University, Durham, North Carolina, United States of America
- Kilimanjaro Christian Medical University College, Tumaini University, Moshi, Tanzania
| | - Blandina T. Mmbaga
- Kilimanjaro Clinical Research Institute, Moshi, United Republic of Tanzania
- Duke Global Health Institute, Duke University, Durham, North Carolina, United States of America
- Kilimanjaro Christian Medical University College, Tumaini University, Moshi, Tanzania
| | - Obed M. Nyasebwa
- Ministry of Livestock and Fisheries, Dodoma, United Republic of Tanzania
| | - Emanuel S. Swai
- Ministry of Livestock and Fisheries, Dodoma, United Republic of Tanzania
| | - Brian Willett
- MRC University of Glasgow Centre for Virus Research, Glasgow, United Kingdom
| | - Sarah Cleaveland
- School of Biodiversity, One Health, and Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
- * E-mail: (WAdG); (SC)
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8
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Campbell Z, Coleman P, Guest A, Kushwaha P, Ramuthivheli T, Osebe T, Perry B, Salt J. Prioritizing smallholder animal health needs in East Africa, West Africa, and South Asia using three approaches: Literature review, expert workshops, and practitioner surveys. Prev Vet Med 2021; 189:105279. [PMID: 33581421 PMCID: PMC8024747 DOI: 10.1016/j.prevetmed.2021.105279] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 12/18/2020] [Accepted: 01/18/2021] [Indexed: 12/15/2022]
Abstract
Managing the health needs of livestock contributes to reducing poverty and improving the livelihoods of smallholder and pastoralist livestock keepers globally. Animal health practitioners, producers, policymakers, and researchers all must prioritize how to mobilize limited resources. This study employed three approaches to prioritize animal health needs in East and West Africa and South Asia to identify diseases and syndromes that impact livestock keepers. The approaches were a) systematic literature review, b) a series of expert workshops, and c) a practitioner survey of veterinarians and para-veterinary professionals. The top constraints that emerged from all three approaches include endo/ ectoparasites, foot and mouth disease, brucellosis, peste des petits ruminants, Newcastle disease, and avian influenza. Expert workshops additionally identified contagious caprine pleuropneumonia, contagious bovine pleuropneumonia, mastitis, and reproductive disorders as constraints not emphasized in the literature review. Practitioner survey results additionally identified nutrition as a constraint for smallholder dairy and pastoralist small ruminant production. Experts attending the workshops agreed most constraints can be managed using existing veterinary technologies and best husbandry practices, which supports a shift away from focusing on individual diseases and new technologies towards addressing systemic challenges that limit access to veterinary services and inputs. Few research studies focused on incidence/ prevalence of disease and impact, suggesting better incorporation of socio-economic impact measures in future research would better represent the interests of livestock keepers.
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Affiliation(s)
- Zoë Campbell
- International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi, 00100, Kenya.
| | - Paul Coleman
- H20 Venture Partners, 33-35 George Street, Oxford, OX1 2AY, United Kingdom
| | - Andrea Guest
- H20 Venture Partners, 33-35 George Street, Oxford, OX1 2AY, United Kingdom
| | - Peetambar Kushwaha
- GALVmed Asia Office, Unit 118 & 120 B, Splendor Forum, Plot No 3, Jasola District Centre, Jasola, New Delhi, 110025, India
| | - Thembinkosi Ramuthivheli
- GALVmed Africa Office, International Livestock Research Institute (ILRI), Swing One, Naivasha Road, Nairobi, Kenya
| | - Tom Osebe
- GALVmed Africa Office, International Livestock Research Institute (ILRI), Swing One, Naivasha Road, Nairobi, Kenya
| | - Brian Perry
- Nuffield College of Clinical Medicine, University of Oxford, United Kingdom; College of Medicine and Veterinary Medicine, University of Edinburgh, Arthurstone House, Meigle, Blairgowrie, PH12 8QW, Scotland, United Kingdom
| | - Jeremy Salt
- GALVmed UK Office, Doherty Building, Pentlands Science Park, Bush Loan, Penicuik Edinburgh, EH26 0PZ, Scotland, United Kingdom
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9
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Kumalija MS, Chilongola JO, Budodo RM, Horumpende PG, Mkumbaye SI, Vianney JM, Mwakapuja RS, Mmbaga BT. Detection of Rift Valley Fever virus inter-epidemic activity in Kilimanjaro Region, North Eastern Tanzania. Glob Health Action 2021; 14:1957554. [PMID: 34415237 PMCID: PMC8381910 DOI: 10.1080/16549716.2021.1957554] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Background Rift Valley Fever virus (RVFV) is a zoonotic arbovirus of public health impact infecting livestock, wildlife, and humans mainly in Africa and other parts of the world. Despite its public health importance, mechanisms of RVFV maintenance during interepidemic periods (IEPS) remain unclear. Objective We aimed to examine comparatively exposure to RVFV between humans and goats and RVFV infection between humans, goats and mosquitoes. Methods A cross sectional study was performed in the Lower Moshi area of the Kilimanjaro region from March to June 2020. RVFV exposure was determined by detecting IgG/IgM to RVFV using a competitive enzyme linked immunosorbent assay whereas infection was determined by real time quantitative polymerase chain reaction (RT-qPCR) assay. Results Results show that the male gender was related to RVFV seropositivity (χ2 = 5.351; p=0.030). Being 50 years and above was related to seropositivity (χ2 =14.430; p=0.006) whereas bed net use, larger numbers of persons living in the same house (>7 persons) and RVFV seropositivity in goats were related to higher seropositivity to RVFV among humans χ2 =6.003; p=0.021, χ2 =23.213; p < 0.001 and χ2 =27.053; p < 0.001), respectively. By the use of RT-qPCR, goats exhibited the highest RVFV infection rate of 4.1%, followed by humans (2.6%), Ae. aegypti (2.3%), and Cx. pipiens complex(1.5%). Likewise, a higher proportion of goats (23.3%) were RVFV seropositive as compared with humans (13.2%). Conclusion Our findings suggest the Lower Moshi area as a potential hotspot for Rift Valley Fever (RVF), posing the danger of being a source of RVFV spread to other areas. Goats had the highest infection rate, suggesting goats as important hosts for virus maintenance during IEPs. We recommend the implementation of strategies that will warrant active RVF surveillance through the identification of RVF hotspots for targeted control of the disease.
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Affiliation(s)
- Medard S Kumalija
- Department of Global Health and Biomedical Sciences, Nelson Mandela Institution of Science and Technology, Arusha, Tanzania
| | - Jaffu O Chilongola
- Department of Medical Biochemistry and Molecular Biology, Kilimanjaro Christian Medical University College, Moshi Tanzania.,Department of Clinical Trials, Kilimanjaro Clinical Research Institute, Moshi, Tanzania
| | - Rule M Budodo
- Department of Clinical Trials, Kilimanjaro Clinical Research Institute, Moshi, Tanzania
| | - Pius G Horumpende
- Department of Public Health and Research, Lugalo Military College of Medical Sciences, Dar Es Salaam, Tanzania
| | - Sixbert I Mkumbaye
- Department of Clinical Trials, Kilimanjaro Clinical Research Institute, Moshi, Tanzania
| | - John-Mary Vianney
- Department of Global Health and Biomedical Sciences, Nelson Mandela Institution of Science and Technology, Arusha, Tanzania
| | - Richard S Mwakapuja
- Department of Bacterial Vaccines, Tanzania Veterinary Laboratory Agency (TVLA), Kibaha, Tanzania
| | - Blandina T Mmbaga
- Department of Clinical Trials, Kilimanjaro Clinical Research Institute, Moshi, Tanzania
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10
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Adamu AM, Enem SI, Ngbede EO, Owolodun OA, Dzikwi AA, Ajagbe OA, Datong DD, Bello GS, Kore M, Yikawe SS, Allam L, Simon AY. Serosurvey on Sheep Unravel Circulation of Rift Valley Fever Virus in Nigeria. ECOHEALTH 2020; 17:393-397. [PMID: 33106981 DOI: 10.1007/s10393-020-01490-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Revised: 12/06/2019] [Accepted: 07/02/2020] [Indexed: 06/11/2023]
Abstract
Rift Valley fever is an arboviral zoonoses causing severe morbidity and mortality among humans and animals in many African countries. A cross-sectional study in populations of sheep reared around the Gidan-Waya Forest Reserve located in Jema'a LGA of Kaduna State, Nigeria to determine the serological evidence of exposure to Rift Valley fever virus (RVFV) using a commercial competitive enzyme-linked immunosorbent assay. Of the 200 sheep sampled, 9 (4.5%; 95 CI 2.23-8.33) were positive for antibodies to the RVFV. The detection of antibodies suggests a covert circulation among the sheep and may be indicative of a subclinical infection.
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Affiliation(s)
- A M Adamu
- Department of Veterinary Public Health and Preventive Medicine, University of Abuja, Abuja, Nigeria.
| | - S I Enem
- Department of Veterinary Public Health and Preventive Medicine, University of Abuja, Abuja, Nigeria
| | - E O Ngbede
- Department of Veterinary Microbiology, Federal University of Agriculture Makurdi, Makurdi, Nigeria
| | - O A Owolodun
- Biotechnology Division, National Veterinary Research Institute, Vom, Nigeria
| | - A A Dzikwi
- Department of Veterinary Public Health and Preventive Medicine, University of Jos, Jos, Nigeria
| | - O A Ajagbe
- Department of Veterinary Microbiology, University of Abuja, Abuja, Nigeria
| | - D D Datong
- Department of Veterinary Public Health and Preventive Medicine, University of Abuja, Abuja, Nigeria
| | - G S Bello
- United Nations Children Fund, Yola, Adamawa State, Nigeria
| | - M Kore
- Department of Veterinary Medicine, Ahmadu Bello University, Zaria, Nigeria
| | - S S Yikawe
- Nigerian Air Force Hospital, Abuja, Nigeria
| | - L Allam
- Veterinary Teaching Hospital, Ahmadu Bello University, Zaria, Nigeria
| | - A Y Simon
- African Centre of Excellence On Neglected Tropical Diseases and Forensic Biotechnology, Ahmadu Bello University, Zaria, Nigeria
- Centre for Blood Research and Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada
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11
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Budodo RM, Horumpende PG, Mkumbaye SI, Mmbaga BT, Mwakapuja RS, Chilongola JO. Serological evidence of exposure to Rift Valley, Dengue and Chikungunya Viruses among agropastoral communities in Manyara and Morogoro regions in Tanzania: A community survey. PLoS Negl Trop Dis 2020; 14:e0008061. [PMID: 32687540 PMCID: PMC7402518 DOI: 10.1371/journal.pntd.0008061] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 08/04/2020] [Accepted: 06/11/2020] [Indexed: 11/19/2022] Open
Abstract
Tanzania has recently experienced outbreaks of dengue in two coastal regions of Dar es Salaam and Tanga. Chikungunya and Rift Valley Fever outbreaks have also been recorded in the past decade. Little is known on the burden of the arboviral disease causing viruses (Dengue, Rift Valley and Chikungunya) endemically in the inter-epidemic periods. We aimed at determining the prevalence of the dengue, rift valley and chikungunya among humans in two geo ecologically distinct sites. The community-based cross-sectional study was conducted in Magugu in Manyara region and Wami-Dakawa in Morogoro region in Tanzania. Venous blood was collected from participants of all age groups, serum prepared from samples and subjected to ELISA tests for RVFV IgG/IgM, DENV IgG/IgM, and CHIKV IgM/IgG. Samples that were positive for IgM ELISA tests were subjected to a quantitative RT PCR for each virus. A structured questionnaire was used to collect socio-demographic information. Data analysis was performed by using SPSSv22. A total of 191 individuals from both sites participated in the study. Only one individual was CHIKV seropositive in Magugu, but none was seropositive or positive for either RVFV or DENV. Of the 122 individuals from Wami-Dakawa site, 16.39% (n = 20) had recent exposure to RVFV while 9.83% (n = 12) were seropositive for CHIKV. All samples were negative by RVFV and CHIKV qPCR. Neither infection nor exposure to DENV was observed in participants from both sites. Being more than 5 in a household, having no formal education and having recently travelled to an urban area were risk factors associated with RVFV and CHIKV seropositivity. We report a considerable exposure to RVFV and CHIKV among Wami-Dakawa residents during the dry season and an absence of exposure of the viruses among humans in Magugu site. In both sites, neither DENV exposure nor infection was detected.
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Affiliation(s)
- Rule M. Budodo
- Kilimanjaro Clinical Research Institute, Moshi, Tanzania
| | - Pius G. Horumpende
- Kilimanjaro Clinical Research Institute, Moshi, Tanzania
- Department of Public Health and Research, Lugalo Military College of Medical Sciences (MCMS) and General Military Hospital (GMH), Dar es Salaam, Tanzania
| | - Sixbert I. Mkumbaye
- Kilimanjaro Clinical Research Institute, Moshi, Tanzania
- Department of Medical Biochemistry and Molecular Biology, Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Blandina T. Mmbaga
- Kilimanjaro Clinical Research Institute, Moshi, Tanzania
- Directorate of Research and Consultancies, Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | | | - Jaffu O. Chilongola
- Kilimanjaro Clinical Research Institute, Moshi, Tanzania
- Department of Medical Biochemistry and Molecular Biology, Kilimanjaro Christian Medical University College, Moshi, Tanzania
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12
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Durand B, Lo Modou M, Tran A, Ba A, Sow F, Belkhiria J, Fall AG, Biteye B, Grosbois V, Chevalier V. Rift Valley fever in northern Senegal: A modelling approach to analyse the processes underlying virus circulation recurrence. PLoS Negl Trop Dis 2020; 14:e0008009. [PMID: 32479505 PMCID: PMC7289439 DOI: 10.1371/journal.pntd.0008009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 06/11/2020] [Accepted: 04/22/2020] [Indexed: 01/12/2023] Open
Abstract
Rift Valley fever (RVF) is endemic in northern Senegal, a Sahelian area characterized by a temporary pond network that drive both RVF mosquito population dynamics and nomadic herd movements. To investigate the mechanisms that explain RVF recurrent circulation, we modelled a realistic epidemiological system at the pond level integrating vector population dynamics, resident and nomadic ruminant herd population dynamics, and nomadic herd movements recorded in Younoufere area. To calibrate the model, serological surveys were performed in 2015–2016 on both resident and nomadic domestic herds in the same area. Mosquito population dynamics were obtained from a published model trained in the same region. Model comparison techniques were used to compare five different scenarios of virus introduction by nomadic herds associated or not with vertical transmission in Aedes vexans. Our serological results confirmed a long lasting RVF endemicity in resident herds (IgG seroprevalence rate of 15.3%, n = 222), and provided the first estimation of RVF IgG seroprevalence in nomadic herds in West Africa (12.4%, n = 660). Multivariate analysis of serological data suggested an amplification of the transmission cycle during the rainy season with a peak of circulation at the end of that season. The best scenario of virus introduction combined yearly introductions of RVFV from 2008 to 2015 (the study period) by nomadic herds, with a proportion of viraemic individuals predicted to be larger in animals arriving during the 2nd half of the rainy season (3.4%). This result is coherent with the IgM prevalence rate (4%) found in nomadic herds sampled during the 2nd half of the rainy season. Although the existence of a vertical transmission mechanism in Aedes cannot be ruled out, our model demonstrates that nomadic movements are sufficient to account for this endemic circulation in northern Senegal. Rift Valley fever (RVF) is one of the most important vector borne disease in Africa, seriously affecting the health of domestic ruminants and humans and leading to severe economic consequences. This disease is endemic in northern Senegal, a Sahelian area characterized by a temporary pond network that drive both RVF mosquito population dynamics and nomadic herd movements. Two non-exclusive mechanisms may support this endemicity: recurrent introductions of the virus by nomadic animals, and vertical transmission of the virus (i.e. from infected female mosquito to eggs) in local Aedes populations. The authors followed resident and nomadic domestic herds for 1 year. They used the data thus obtained to model a realistic epidemiological system at the pond level integrating vector population dynamics, resident and nomadic ruminant herd population dynamics. They found that the best scenario explaining RVF remanence combined yearly introductions of RVFV by nomadic herds, with a viraemic proportion predicted to be larger in animals arriving during the 2nd half of the rainy season, which is consistent with an amplification of virus circulation in the area during the rainy season. Although the existence of a vertical transmission mechanism in Aedes cannot be ruled out, their results demonstrates that nomadic movements are sufficient to account for this endemic circulation in northern Senegal.
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Affiliation(s)
- Benoit Durand
- Epidemiology Unit, Laboratory for Animal Health, French Agency for Food, Environmental and Occupational Health and Safety (ANSES), University Paris-Est, Maisons-Alfort, France
- * E-mail: (BD); (VC)
| | | | - Annelise Tran
- CIRAD, UMR TETIS, Sainte-Clotilde, Réunion, France
- CIRAD, UMR ASTRE, Montpellier, France
- Université Montpellier, Montpellier, France
| | - Aminata Ba
- Institut Sénégalais de Recherche Agricole (ISRA), Dakar, Sénégal
| | - Fafa Sow
- Institut Sénégalais de Recherche Agricole (ISRA), Dakar, Sénégal
| | - Jaber Belkhiria
- Center for Animal Disease Modeling and Surveillance, Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California Davis, California, United States of America
| | | | - Biram Biteye
- Institut Sénégalais de Recherche Agricole (ISRA), Dakar, Sénégal
| | | | - Véronique Chevalier
- CIRAD, UMR ASTRE, Montpellier, France
- CIRAD, UMR ASTRE, Phnom Penh, Cambodia
- Epidemiology and Public Health Unit, Institut Pasteur du Cambodge, Phnom Penh, Cambodia
- * E-mail: (BD); (VC)
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13
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Bilgin Z, Turan N, Cizmecigil UY, Altan E, Esatgil MU, Yilmaz A, Aydin O, Kocazeybek B, Richt JA, Yilmaz H. Investigation of Vector-Borne Viruses in Ticks, Mosquitos, and Ruminants in the Thrace District of Turkey. Vector Borne Zoonotic Dis 2020; 20:670-679. [PMID: 32397953 DOI: 10.1089/vbz.2019.2532] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
There is a considerable increase in vector-borne zoonotic diseases around the world, including Turkey, such as Crimean-Congo hemorrhagic fever (CCHF), tick borne encephalitis (TBE), Rift Valley fever (RVF), and West Nile fever (WNF), causing disease and death in humans and animals and significant economical losses. Hence, the aim of this study was to investigate the presence of CCHF virus (CCHFV) and TBE virus (TBEV) in ticks and RVF virus (RVFV) and WNF virus (WNV) in mosquitos, as well as in sheep and cattle, in the Thrace district of the Marmara region, which borders Bulgaria and Greece. Buffy-coat samples from 86 cattle and 81 sheep, as well as 563 ticks and 7390 mosquitos, were collected and examined by quantitative real-time RT-PCR for the presence of CCHFV, TBEV, RVFV, and WNV. All buffy-coat samples from cattle and sheep were negative for these viruses. Similarly, all tick samples were negative for CCHFV-RNA and TBEV-RNA. Among 245 pools representing 7390 mosquitos, only 1 pool sample was found to be positive for WNV-RNA and was confirmed by sequencing. Phylogenetic analysis revealed that it was WNV lineage-2. No RVFV-RNA was detected in the 245 mosquito pools. In conclusion, results of this study indicate that CCHFV, TBEV, and RVFV are not present in livestock and respective vectors in the Thrace district of Marmara region of Turkey, whereas WNV-RNA was found in mosquitos from this region.
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Affiliation(s)
- Zahide Bilgin
- Department of Parasitology, Veterinary Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Nuri Turan
- Department of Virology, Veterinary Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Utku Y Cizmecigil
- Department of Virology, Veterinary Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Eda Altan
- Department of Virology, Veterinary Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Meltem Ulutas Esatgil
- Department of Parasitology, Veterinary Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Aysun Yilmaz
- Department of Virology, Veterinary Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Ozge Aydin
- Department of Virology, Veterinary Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Bekir Kocazeybek
- Department of Microbiology, Cerrahpasa Faculty of Medicine, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Juergen A Richt
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, USA
| | - Huseyin Yilmaz
- Department of Virology, Veterinary Faculty, Istanbul University-Cerrahpasa, Istanbul, Turkey
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14
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Ngoshe YB, Avenant A, Rostal MK, Karesh WB, Paweska JT, Bagge W, Jansen van Vuren P, Kemp A, Cordel C, Msimang V, Thompson PN. Patterns of Rift Valley fever virus seropositivity in domestic ruminants in central South Africa four years after a large outbreak. Sci Rep 2020; 10:5489. [PMID: 32218486 PMCID: PMC7099094 DOI: 10.1038/s41598-020-62453-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 03/09/2020] [Indexed: 11/16/2022] Open
Abstract
Rift Valley fever (RVF) is a mosquito-borne viral zoonosis showing complex epidemiological patterns that are poorly understood in South Africa. Large outbreaks occur in the central interior at long, irregular intervals, most recently in 2010–2011; however, the level of herd immunity of ruminant livestock, a key determinant of outbreaks, is unknown. During 2015–2016 a cross-sectional study on 234 randomly-selected farms investigated the prevalence, patterns of, and factors associated with, antibodies to RVF virus (RVFV) in livestock in an area heavily affected by that outbreak. A RVFV inhibition ELISA was used to screen 977 cattle, 1,549 sheep and 523 goats and information on potential risk factors was collected using a comprehensive questionnaire. The estimated RVFV seroprevalence, adjusted for survey design, was 42.9% in cattle, 28.0% in sheep and 9.3% in goats, showing a high degree of farm-level clustering. Seroprevalence increased with age and was higher on private vs. communal land, on farms with seasonal pans (temporary, shallow wetlands) and perennial rivers and in recently vaccinated animals. Seropositivity amongst unvaccinated animals born after the last outbreak indicates likely viral circulation during the post-epidemic period. The current level of herd immunity in livestock may be insufficient to prevent another large outbreak, should suitable conditions recur.
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Affiliation(s)
- Yusuf B Ngoshe
- Epidemiology Section, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa
| | - Alida Avenant
- Epidemiology Section, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa
| | - Melinda K Rostal
- EcoHealth Alliance, 460 West 34th Street - 17th Floor, New York, NY, 10001, USA
| | - William B Karesh
- EcoHealth Alliance, 460 West 34th Street - 17th Floor, New York, NY, 10001, USA
| | - Janusz T Paweska
- Centre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Sandringham, Johannesburg, South Africa
| | - Whitney Bagge
- EcoHealth Alliance, 460 West 34th Street - 17th Floor, New York, NY, 10001, USA
| | - Petrus Jansen van Vuren
- Centre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Sandringham, Johannesburg, South Africa
| | - Alan Kemp
- Centre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Sandringham, Johannesburg, South Africa
| | | | - Veerle Msimang
- Epidemiology Section, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa.,Centre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases, National Health Laboratory Service, Sandringham, Johannesburg, South Africa
| | - Peter N Thompson
- Epidemiology Section, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa.
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15
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Shoemaker TR, Nyakarahuka L, Balinandi S, Ojwang J, Tumusiime A, Mulei S, Kyondo J, Lubwama B, Sekamatte M, Namutebi A, Tusiime P, Monje F, Mayanja M, Ssendagire S, Dahlke M, Kyazze S, Wetaka M, Makumbi I, Borchert J, Zufan S, Patel K, Whitmer S, Brown S, Davis WG, Klena JD, Nichol ST, Rollin PE, Lutwama J. First Laboratory-Confirmed Outbreak of Human and Animal Rift Valley Fever Virus in Uganda in 48 Years. Am J Trop Med Hyg 2020; 100:659-671. [PMID: 30675833 PMCID: PMC6402942 DOI: 10.4269/ajtmh.18-0732] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
In March 2016, an outbreak of Rift Valley fever (RVF) was identified in Kabale district, southwestern Uganda. A comprehensive outbreak investigation was initiated, including human, livestock, and mosquito vector investigations. Overall, four cases of acute, nonfatal human disease were identified, three by RVF virus (RVFV) reverse transcriptase polymerase chain reaction (RT-PCR), and one by IgM and IgG serology. Investigations of cattle, sheep, and goat samples from homes and villages of confirmed and probable RVF cases and the Kabale central abattoir found that eight of 83 (10%) animals were positive for RVFV by IgG serology; one goat from the home of a confirmed case tested positive by RT-PCR. Whole genome sequencing from three clinical specimens was performed and phylogenetic analysis inferred the relatedness of 2016 RVFV with the 2006–2007 Kenya-2 clade, suggesting previous introduction of RVFV into southwestern Uganda. An entomological survey identified three of 298 pools (1%) of Aedes and Coquillettidia species that were RVFV positive by RT-PCR. This was the first identification of RVFV in Uganda in 48 years and the 10th independent viral hemorrhagic fever outbreak to be confirmed in Uganda since 2010.
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Affiliation(s)
- Trevor R Shoemaker
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia.,Viral Special Pathogens Branch, Centers for Disease Control and Prevention-Uganda, Entebbe, Uganda
| | - Luke Nyakarahuka
- Department of Biosecurity, Ecosystems and Veterinary Public Health, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda.,Department of Arbovirology, Emerging and Reemerging Infectious Diseases, Uganda Virus Research Institute, Entebbe, Uganda
| | - Stephen Balinandi
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention-Uganda, Entebbe, Uganda
| | - Joseph Ojwang
- Global Health Security Unit, Centers for Disease Control and Prevention-Uganda, Kampala, Uganda
| | - Alex Tumusiime
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention-Uganda, Entebbe, Uganda
| | - Sophia Mulei
- Department of Arbovirology, Emerging and Reemerging Infectious Diseases, Uganda Virus Research Institute, Entebbe, Uganda
| | - Jackson Kyondo
- Department of Biosecurity, Ecosystems and Veterinary Public Health, College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | | | | | | | | | - Fred Monje
- Ministry of Agriculture, Animal Industry and Fisheries, Kampala, Uganda
| | - Martin Mayanja
- Department of Arbovirology, Emerging and Reemerging Infectious Diseases, Uganda Virus Research Institute, Entebbe, Uganda
| | | | - Melissa Dahlke
- Public Health Emergency Operations Centre, Ministry of Health, Kampala, Uganda
| | - Simon Kyazze
- Public Health Emergency Operations Centre, Ministry of Health, Kampala, Uganda
| | - Milton Wetaka
- Public Health Emergency Operations Centre, Ministry of Health, Kampala, Uganda
| | - Issa Makumbi
- Public Health Emergency Operations Centre, Ministry of Health, Kampala, Uganda
| | - Jeff Borchert
- Global Health Security Unit, Centers for Disease Control and Prevention-Uganda, Kampala, Uganda
| | - Sara Zufan
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Ketan Patel
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Shannon Whitmer
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Shelley Brown
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - William G Davis
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - John D Klena
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Stuart T Nichol
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Pierre E Rollin
- Viral Special Pathogens Branch, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Julius Lutwama
- Department of Arbovirology, Emerging and Reemerging Infectious Diseases, Uganda Virus Research Institute, Entebbe, Uganda
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Tshilenge GM, Mulumba MLK, Misinzo G, Noad R, Dundon WG. Rift Valley fever virus in small ruminants in the Democratic Republic of the Congo. ACTA ACUST UNITED AC 2019; 86:e1-e5. [PMID: 31714136 PMCID: PMC6852419 DOI: 10.4102/ojvr.v86i1.1737] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 05/02/2019] [Accepted: 05/07/2019] [Indexed: 11/01/2022]
Abstract
Rift Valley fever (RVF) is a zoonotic viral disease caused by the RVF phlebovirus (RVFV) that infects a variety of animal species including sheep and goats. Sera (n = 893) collected between 2013 and 2015 from randomly selected indigenous sheep and goats in seven provinces of the Democratic Republic of the Congo (DRC) were tested for the presence of specific immunoglobulin G (IgG) and M (IgM) against RVFV, using two commercially available enzyme-linked immunosorbent assays. The reverse transcription polymerase chain reaction (RT-PCR) was also used to detect RVFV nucleic acid. There was significant variation in true seroprevalence of RVFV for both sheep and goats between the seven provinces investigated. Values ranged from 0.0 (95% confidence interval [CI] 0.0-6.55) to 23.81 (95% CI 12.03-41.76) for goat and 0.0 (95% CI 0.0-7.56) to 37.11 (95% CI 15.48-65.94) for sheep, respectively. One serum (1.85%) out of 54 that tested positive for IgG was found to be IgM-positive. This same sample was also positive by RT-PCR indicating an active or recent infection. These findings report the presence of RVFV in small ruminants in the DRC for the first time and indicate variations in exposure to the virus in different parts of the country.
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Affiliation(s)
- Georges M Tshilenge
- Department of Preclinical Medicine, Faculty of Veterinary Medicine, University of Kinshasa, Kinshasa XI.
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Opayele AV, Ndiana LA, Odaibo GN, Olaleye DO. Serological evidence of Rift Valley fever virus infection in slaughtered ruminants in Nigeria. J Immunoassay Immunochem 2019; 40:367-377. [PMID: 31081465 DOI: 10.1080/15321819.2019.1609498] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The risk of exposure of slaughterhouse workers to Rift Valley fever (RVF) virus-infected animals in Nigeria was assessed by determining the prevalence of anti-RVF IgM in cattle, goats and sheep slaughtered in a major abattoir in Ibadan, Nigeria. Blood samples were collected from 290 animals in Bodija Municipal abattoir, Ibadan, Nigeria in January and February 2017 and analyzed for the presence of RVF virus using IgM Enzyme-Linked Immunosorbent Assay (ELISA) and Reverse Transcriptase Polymerase Chain Reaction (RT-PCR) for detection of the virus RNA. Descriptive statistics was used to analyze data. Overall, an IgM prevalence of 0.7% (2/290) was found among the blood samples of the animals, suggesting recent exposure to the virus. Antibody was detected in the sera from a cow and one goat. RVF virus RNA was not detected in the 2 IgM positive blood samples. There was no statistically significant relationship between RVF IgM infection and some variables of the animals, including age, sex and breed (p ≥ 0.05). Results of this study indicate active RVF virus transmission in domestic livestock in Nigeria. The study emphasizes the need to embark on monitoring of human and animal populations to prevent outbreak of the virus in the country.
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Affiliation(s)
| | - Linda Amarachi Ndiana
- b Department of Veterinary Microbiology, College of Veterinary Medicine , Michael Okpara University of Agriculture , Umudike , Nigeria
| | | | - David Olufemi Olaleye
- a Department of Virology, College of Medicine , University of Ibadan , Ibadan , Nigeria
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18
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van den Bergh C, Venter EH, Swanepoel R, Thompson PN. High seroconversion rate to Rift Valley fever virus in cattle and goats in far northern KwaZulu-Natal, South Africa, in the absence of reported outbreaks. PLoS Negl Trop Dis 2019; 13:e0007296. [PMID: 31050673 PMCID: PMC6519843 DOI: 10.1371/journal.pntd.0007296] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 05/15/2019] [Accepted: 03/12/2019] [Indexed: 11/19/2022] Open
Abstract
Background Rift Valley fever (RVF) is a mosquito-borne zoonotic disease characterized in South Africa by large epidemics amongst ruminant livestock at very long, irregular intervals, mainly in the central interior. However, the presence and patterns of occurrence of the virus in the eastern parts of the country are poorly known. This study aimed to detect the presence of RVF virus (RVFV) in cattle and goats in far northern KwaZulu-Natal province and to estimate the prevalence of antibodies to the virus and the incidence rate of seroconversion. Methodology Cross-sectional studies were performed in communally farmed cattle (n = 423) and goats (n = 104), followed by longitudinal follow-up of seronegative livestock (n = 253) 14 times over 24 months, representing 160.3 animal-years at risk. Exposure to RVFV was assessed using an IgG sandwich ELISA and a serum neutralization test (SNT) and seroconversion was assessed using SNT. Incidence density was estimated and compared using multivariable Poisson models and hazard of seroconversion was estimated over time. Principal findings Initial overall seroprevalence was 34.0% (95%CI: 29.5–38.8%) in cattle and 31.7% (95%CI: 22.9–41.6%) in goats, varying by locality from 18–54%. Seroconversions to RVFV based on SNT were detected throughout the year, with the incidence rate peaking during the high rainfall months of January to March, and differed considerably between years. Overall seroconversion rate in cattle was 0.59 per animal-year (95% CI: 0.46–0.75) and in goats it was 0.41 per animal-year (95% CI: 0.25–0.64), varying significantly over short distances. Conclusions/Significance The high seroprevalence in all age groups and evidence of year-round viral circulation provide evidence for a hyperendemic situation in the study area. This is the first study to directly estimate infection rate of RVFV in livestock in an endemic area in the absence of reported outbreaks and provides the basis for further investigation of factors affecting viral circulation and mechanisms for virus survival during interepidemic periods. Rift Valley fever (RVF) is a mosquito-transmitted viral disease that may cause large epidemics in domestic livestock and in humans. Although currently largely confined to Africa, it is of international concern due to its ability to spread and become established in areas where suitable mosquito vectors occur. Outbreaks occur sporadically, associated with conditions favourable for proliferation of mosquito populations, such as high rainfall and flooding, yet their location and timing remain difficult to predict. In other areas there is evidence that RVF virus is endemic and may circulate without causing outbreaks. However, the location and extent of such areas is poorly known, as is the transmission dynamics of the virus in those areas. In this paper, we report the existence of such an area of endemic RVF virus transmission on the tropical coastal plain of South Africa bordering Mozambique, where we found a high rate of exposure of domestic cattle and goats to the naturally circulating virus over a two-year period, with no outbreaks being reported. Research in such areas will help us to assess the potential for spread of the virus to other areas and also to better understand the behaviour of the virus during periods between epidemics.
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Affiliation(s)
- Carien van den Bergh
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, Gauteng, South Africa
| | - Estelle H. Venter
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, Gauteng, South Africa
- College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, Queensland, Australia
| | - Robert Swanepoel
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, Gauteng, South Africa
| | - Peter N. Thompson
- Epidemiology Section, Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, Gauteng, South Africa
- * E-mail:
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19
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Association between Rift Valley fever virus seroprevalences in livestock and humans and their respective intra-cluster correlation coefficients, Tana River County, Kenya. Epidemiol Infect 2018; 147:e67. [PMID: 30516123 PMCID: PMC6518590 DOI: 10.1017/s0950268818003242] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
We implemented a cross-sectional study in Tana River County, Kenya, a Rift Valley fever (RVF)-endemic area, to quantify the strength of association between RVF virus (RVFv) seroprevalences in livestock and humans, and their respective intra-cluster correlation coefficients (ICCs). The study involved 1932 livestock from 152 households and 552 humans from 170 households. Serum samples were collected and screened for anti-RVFv immunoglobulin G (IgG) antibodies using inhibition IgG enzyme-linked immunosorbent assay (ELISA). Data collected were analysed using generalised linear mixed effects models, with herd/household and village being fitted as random variables. The overall RVFv seroprevalences in livestock and humans were 25.41% (95% confidence interval (CI) 23.49–27.42%) and 21.20% (17.86–24.85%), respectively. The presence of at least one seropositive animal in a household was associated with an increased odds of exposure in people of 2.23 (95% CI 1.03–4.84). The ICCs associated with RVF virus seroprevalence in livestock were 0.30 (95% CI 0.19–0.44) and 0.22 (95% CI 0.12–0.38) within and between herds, respectively. These findings suggest that there is a greater variability of RVF virus exposure between than within herds. We discuss ways of using these ICC estimates in observational surveys for RVF in endemic areas and postulate that the design of the sentinel herd surveillance should consider patterns of RVF clustering to enhance its effectiveness as an early warning system for RVF epidemics.
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Lo Iacono G, Cunningham AA, Bett B, Grace D, Redding DW, Wood JLN. Environmental limits of Rift Valley fever revealed using ecoepidemiological mechanistic models. Proc Natl Acad Sci U S A 2018; 115:E7448-E7456. [PMID: 30021855 PMCID: PMC6077718 DOI: 10.1073/pnas.1803264115] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Vector-borne diseases (VBDs) of humans and domestic animals are a significant component of the global burden of disease and a key driver of poverty. The transmission cycles of VBDs are often strongly mediated by the ecological requirements of the vectors, resulting in complex transmission dynamics, including intermittent epidemics and an unclear link between environmental conditions and disease persistence. An important broader concern is the extent to which theoretical models are reliable at forecasting VBDs; infection dynamics can be complex, and the resulting systems are highly unstable. Here, we examine these problems in detail using a case study of Rift Valley fever (RVF), a high-burden disease endemic to Africa. We develop an ecoepidemiological, compartmental, mathematical model coupled to the dynamics of ambient temperature and water availability and apply it to a realistic setting using empirical environmental data from Kenya. Importantly, we identify the range of seasonally varying ambient temperatures and water-body availability that leads to either the extinction of mosquito populations and/or RVF (nonpersistent regimens) or the establishment of long-term mosquito populations and consequently, the endemicity of the RVF infection (persistent regimens). Instabilities arise when the range of the environmental variables overlaps with the threshold of persistence. The model captures the intermittent nature of RVF occurrence, which is explained as low-level circulation under the threshold of detection, with intermittent emergence sometimes after long periods. Using the approach developed here opens up the ability to improve predictions of the emergence and behaviors of epidemics of many other important VBDs.
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Affiliation(s)
- Giovanni Lo Iacono
- Department of Veterinary Medicine, Disease Dynamics Unit, University of Cambridge, Cambridge CB3 0ES, United Kingdom;
- Public Health England, Didcot, Oxford OX11 0RQ, United Kingdom
- School of Veterinary Medicine, University of Surrey, Guildford GU2 7AL, United Kingdom
| | - Andrew A Cunningham
- Institute of Zoology, Zoological Society of London, London NW1 4RY, United Kingdom
| | - Bernard Bett
- Animal and Human Health Program, International Livestock Research Institute, Nairobi, 00100 Kenya
| | - Delia Grace
- Animal and Human Health Program, International Livestock Research Institute, Nairobi, 00100 Kenya
| | - David W Redding
- Centre for Biodiversity and Environment Research, Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, United Kingdom
| | - James L N Wood
- Department of Veterinary Medicine, Disease Dynamics Unit, University of Cambridge, Cambridge CB3 0ES, United Kingdom
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Clark MHA, Warimwe GM, Di Nardo A, Lyons NA, Gubbins S. Systematic literature review of Rift Valley fever virus seroprevalence in livestock, wildlife and humans in Africa from 1968 to 2016. PLoS Negl Trop Dis 2018; 12:e0006627. [PMID: 30036382 PMCID: PMC6072204 DOI: 10.1371/journal.pntd.0006627] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 08/02/2018] [Accepted: 06/22/2018] [Indexed: 02/03/2023] Open
Abstract
Background Rift Valley fever virus (RVFV) is a zoonotic arbovirus that causes severe disease in livestock and humans. The virus has caused recurrent outbreaks in Africa and the Arabian Peninsula since its discovery in 1931. This review sought to evaluate RVFV seroprevalence across the African continent in livestock, wildlife and humans in order to understand the spatio-temporal distribution of RVFV seroprevalence and to identify knowledge gaps and areas requiring further research. Risk factors associated with seropositivity were identified and study designs evaluated to understand the validity of their results. Methodology The Preferred Reporting of Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used to produce a protocol to systematically search for RVFV seroprevalence studies in PubMed and Web of Science databases. The Strengthening the Reporting of Observational studies in Epidemiology (STROBE) statement guided the evaluation of study design and analyses. Principal findings A total of 174 RVFV seroprevalence studies in 126 articles fulfilled the inclusion criteria. RVFV seroprevalence was recorded in 31 African countries from 1968 to 2016 and varied by time, species and country. RVFV seroprevalence articles including either livestock and humans or livestock and wildlife seroprevalence records were limited in number (8/126). No articles considered wildlife, livestock and human seroprevalence concurrently, nor wildlife and humans alone. Many studies did not account for study design bias or the sensitivity and specificity of diagnostic tests. Conclusions Future research should focus on conducting seroprevalence studies at the wildlife, livestock and human interface to better understand the nature of cross-species transmission of RVFV. Reporting should be more transparent and biases accounted for in future seroprevalence research to understand the true burden of disease on the African continent. Rift Valley fever virus (RVFV) is a vector-borne virus that infects wildlife and livestock, and can subsequently spread to humans. Due to the nature of the disease it has the potential to cause substantial economic and public health impacts. Rift Valley Fever (RVF) has been identified in Africa and the Arabian Peninsula, but has the potential to spread more widely. This systematic review assessed the distribution of RVF in livestock and humans in Africa by collating all the relevant studies we could find, extracting the data and critically evaluating them. Understanding when and where RVF has occurred in Africa and why some animals and humans get disease helps target control strategies and, in particular, those that reduce spread from livestock to humans. Furthermore, by evaluating past studies we can ensure that future ones are more robust and reproducible, so they can help us better understand the disease.
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Affiliation(s)
- Madeleine H. A. Clark
- Transmission Biology Group, The Pirbright Institute, Pirbright, Woking, United Kingdom
- The Jenner Institute, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- * E-mail:
| | - George M. Warimwe
- Biosciences Department, Kenya Medical Research Institute-Wellcome Trust Research Programme, Kilifi, Kenya
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Antonello Di Nardo
- Vesicular Disease Reference Laboratories, The Pirbright Institute, Pirbright, Woking, United Kingdom
| | - Nicholas A. Lyons
- Vesicular Disease Reference Laboratories, The Pirbright Institute, Pirbright, Woking, United Kingdom
| | - Simon Gubbins
- Transmission Biology Group, The Pirbright Institute, Pirbright, Woking, United Kingdom
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Nyakarahuka L, de St. Maurice A, Purpura L, Ervin E, Balinandi S, Tumusiime A, Kyondo J, Mulei S, Tusiime P, Lutwama J, Klena JD, Brown S, Knust B, Rollin PE, Nichol ST, Shoemaker TR. Prevalence and risk factors of Rift Valley fever in humans and animals from Kabale district in Southwestern Uganda, 2016. PLoS Negl Trop Dis 2018; 12:e0006412. [PMID: 29723189 PMCID: PMC5953497 DOI: 10.1371/journal.pntd.0006412] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 05/15/2018] [Accepted: 03/26/2018] [Indexed: 01/06/2023] Open
Abstract
Background Rift Valley fever (RVF) is a zoonotic disease caused by Rift Valley fever virus (RVFV) found in Africa and the Middle East. Outbreaks can cause extensive morbidity and mortality in humans and livestock. Following the diagnosis of two acute human RVF cases in Kabale district, Uganda, we conducted a serosurvey to estimate RVFV seroprevalence in humans and livestock and to identify associated risk factors. Methods Humans and animals at abattoirs and villages in Kabale district were sampled. Persons were interviewed about RVFV exposure risk factors. Human blood was tested for anti-RVFV IgM and IgG, and animal blood for anti-RVFV IgG. Principal findings 655 human and 1051 animal blood samples were collected. Anti-RVFV IgG was detected in 78 (12%) human samples; 3 human samples (0.5%) had detectable IgM only, and 7 (1%) had both IgM and IgG. Of the 10 IgM-positive persons, 2 samples were positive for RVFV by PCR, confirming recent infection. Odds of RVFV seropositivity were greater in participants who were butchers (odds ratio [OR] 5.1; 95% confidence interval [95% CI]: 1.7–15.1) and those who reported handling raw meat (OR 3.4; 95% CI 1.2–9.8). No persons under age 20 were RVFV seropositive. The overall animal seropositivity was 13%, with 27% of cattle, 7% of goats, and 4% of sheep seropositive. In a multivariate logistic regression, cattle species (OR 9.1; 95% CI 4.1–20.5), adult age (OR 3.0; 95% CI 1.6–5.6), and female sex (OR 2.1; 95%CI 1.0–4.3) were significantly associated with animal seropositivity. Individual human seropositivity was significantly associated with animal seropositivity by subcounty after adjusting for sex, age, and occupation (p < 0.05). Conclusions Although no RVF cases had been detected in Uganda from 1968 to March 2016, our study suggests that RVFV has been circulating undetected in both humans and animals living in and around Kabale district. RVFV seropositivity in humans was associated with occupation, suggesting that the primary mode of RVFV transmission to humans in Kabale district could be through contact with animal blood or body fluids. Viral hemorrhagic fevers are known to cause high morbidity and mortality and pose a serious threat to human and animal populations in endemic countries. An outbreak of Rift Valley fever was detected in Kabale district in March, 2016 and identified the first human cases in Uganda since 1968. There was a need to perform a rapid assessment of the burden of Rift valley fever in Kabale district, identify undetected acute cases, identify risk factors associated with human disease, identify areas at high-risk or future infections, and to determine if this was a newly emerging infection or an endemic disease. Our study found the seroprevalence to be as high as 28% in humans and 36% in animals within some subcounties of Kabale district. Human seropositivity correlated with animal seropositivity, suggesting that animal to human transmission may be the predominant mode of virus spread. Our findings also suggest that this virus may have been endemic for many years prior to these human cases being identified.
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Affiliation(s)
- Luke Nyakarahuka
- Uganda Virus Research Institute, Department of Arbovirology, Emerging and Re-emerging Infections, Entebbe, Uganda
| | - Annabelle de St. Maurice
- Centers for Disease Control and Prevention, Division of High Consequence Pathogens and Pathology, Viral Special Pathogens Branch, Atlanta, Georgia, United States of America
- University of California Los Angeles, Division of Pediatric Infectious Disease, Los Angeles, CA
| | - Lawrence Purpura
- Centers for Disease Control and Prevention, Division of High Consequence Pathogens and Pathology, Viral Special Pathogens Branch, Atlanta, Georgia, United States of America
| | - Elizabeth Ervin
- Centers for Disease Control and Prevention, Division of High Consequence Pathogens and Pathology, Viral Special Pathogens Branch, Atlanta, Georgia, United States of America
| | - Stephen Balinandi
- Centers for Disease Control and Prevention, Division of High Consequence Pathogens and Pathology, Viral Special Pathogens Branch, Entebbe, Uganda
| | - Alex Tumusiime
- Centers for Disease Control and Prevention, Division of High Consequence Pathogens and Pathology, Viral Special Pathogens Branch, Entebbe, Uganda
| | - Jackson Kyondo
- Uganda Virus Research Institute, Department of Arbovirology, Emerging and Re-emerging Infections, Entebbe, Uganda
| | - Sophia Mulei
- Uganda Virus Research Institute, Department of Arbovirology, Emerging and Re-emerging Infections, Entebbe, Uganda
| | | | - Julius Lutwama
- Uganda Virus Research Institute, Department of Arbovirology, Emerging and Re-emerging Infections, Entebbe, Uganda
| | - John D. Klena
- Centers for Disease Control and Prevention, Division of High Consequence Pathogens and Pathology, Viral Special Pathogens Branch, Atlanta, Georgia, United States of America
| | - Shelley Brown
- Centers for Disease Control and Prevention, Division of High Consequence Pathogens and Pathology, Viral Special Pathogens Branch, Atlanta, Georgia, United States of America
| | - Barbara Knust
- Centers for Disease Control and Prevention, Division of High Consequence Pathogens and Pathology, Viral Special Pathogens Branch, Atlanta, Georgia, United States of America
| | - Pierre E. Rollin
- Centers for Disease Control and Prevention, Division of High Consequence Pathogens and Pathology, Viral Special Pathogens Branch, Atlanta, Georgia, United States of America
| | - Stuart T. Nichol
- Centers for Disease Control and Prevention, Division of High Consequence Pathogens and Pathology, Viral Special Pathogens Branch, Atlanta, Georgia, United States of America
| | - Trevor R. Shoemaker
- Centers for Disease Control and Prevention, Division of High Consequence Pathogens and Pathology, Viral Special Pathogens Branch, Atlanta, Georgia, United States of America
- Centers for Disease Control and Prevention, Division of High Consequence Pathogens and Pathology, Viral Special Pathogens Branch, Entebbe, Uganda
- * E-mail:
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Métras R, Fournié G, Dommergues L, Camacho A, Cavalerie L, Mérot P, Keeling MJ, Cêtre-Sossah C, Cardinale E, Edmunds WJ. Drivers for Rift Valley fever emergence in Mayotte: A Bayesian modelling approach. PLoS Negl Trop Dis 2017; 11:e0005767. [PMID: 28732006 PMCID: PMC5540619 DOI: 10.1371/journal.pntd.0005767] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 08/02/2017] [Accepted: 06/30/2017] [Indexed: 11/28/2022] Open
Abstract
Rift Valley fever (RVF) is a major zoonotic and arboviral hemorrhagic fever. The conditions leading to RVF epidemics are still unclear, and the relative role of climatic and anthropogenic factors may vary between ecosystems. Here, we estimate the most likely scenario that led to RVF emergence on the island of Mayotte, following the 2006-2007 African epidemic. We developed the first mathematical model for RVF that accounts for climate, animal imports and livestock susceptibility, which is fitted to a 12-years dataset. RVF emergence was found to be triggered by the import of infectious animals, whilst transmissibility was approximated as a linear or exponential function of vegetation density. Model forecasts indicated a very low probability of virus endemicity in 2017, and therefore of re-emergence in a closed system (i.e. without import of infected animals). However, the very high proportion of naive animals reached in 2016 implies that the island remains vulnerable to the import of infectious animals. We recommend reinforcing surveillance in livestock, should RVF be reported is neighbouring territories. Our model should be tested elsewhere, with ecosystem-specific data.
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Affiliation(s)
- Raphaëlle Métras
- Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Guillaume Fournié
- Veterinary Epidemiology, Economics and Public Health group, Department of Pathobiology and Population Sciences, The Royal Veterinary College, Hatfield, United Kingdom
| | - Laure Dommergues
- GDS Mayotte-Coopérative Agricole des Eleveurs Mahorais, Coconi, Mayotte, France
| | - Anton Camacho
- Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Epicentre, Paris, France
| | - Lisa Cavalerie
- Centre de coopération internationale en recherche agronomique pour le développement (CIRAD) UMR ASTRE, Cyroi platform, Sainte Clotilde, La Réunion, France
- Institut National de Recherche Agronomique (INRA) UMR 1309 ASTRE, Montpellier, France
- Bureau de la Santé Animale, Direction Générale de l’Alimentation, Paris, France
- Université de La Réunion, Saint Denis, France
| | - Philippe Mérot
- Direction de l’Alimentation, de l’Agriculture et de la Forêt de Mayotte, Mamoudzou, France
| | - Matt J. Keeling
- WIDER, Warwick University, Coventry, United Kingdom
- Life Sciences, Warwick University, Coventry, United Kingdom
- Mathematics Institute, Warwick University, Coventry, United Kingdom
| | - Catherine Cêtre-Sossah
- Centre de coopération internationale en recherche agronomique pour le développement (CIRAD) UMR ASTRE, Cyroi platform, Sainte Clotilde, La Réunion, France
- Institut National de Recherche Agronomique (INRA) UMR 1309 ASTRE, Montpellier, France
| | - Eric Cardinale
- Centre de coopération internationale en recherche agronomique pour le développement (CIRAD) UMR ASTRE, Cyroi platform, Sainte Clotilde, La Réunion, France
- Institut National de Recherche Agronomique (INRA) UMR 1309 ASTRE, Montpellier, France
| | - W. John Edmunds
- Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom
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Maganga GD, Abessolo Ndong AL, Mikala Okouyi CS, Makiala Mandanda S, N'Dilimabaka N, Pinto A, Agossou E, Cossic B, Akue JP, Leroy EM. Serological Evidence for the Circulation of Rift Valley Fever Virus in Domestic Small Ruminants in Southern Gabon. Vector Borne Zoonotic Dis 2017; 17:443-446. [PMID: 28387600 DOI: 10.1089/vbz.2016.2065] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Rift Valley fever (RVF) is a zoonotic disease, which caused several epidemics in humans in many countries of Africa. Using an inhibition enzyme-linked immunosorbent assay (ELISA), real-time reverse transcription PCR, and nested one-step reverse transcription PCR, we conducted a cross-sectional study in populations of sheep and goats from the Mongo County in 2014 to determine the circulation of the Rift Valley fever virus (RVFV) in small ruminants from this area. From a total of 201 small ruminants (95 sheep and 106 goats), the overall IgG seroprevalence against the RVFV was 6.47% (13/201). No RVFV RNA was detected in the animal plasmas. Logistic regression analysis showed that age, species, sex, and locality were not the significant risk factors. The findings of this study highlight the risk of RVF for domestic ruminants bred in this region and for the human rural population living in contact with these animals and they emphasize the need to develop adequate control measures to limit this threat.
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Affiliation(s)
- Gael Darren Maganga
- 1 Centre International de Recherches Médicales de Franceville (CIRMF) , Franceville, Gabon .,2 Institut National Supérieur d'Agronomie et de Biotechnologies (INSAB) , Franceville, Gabon
| | | | | | | | - Nadine N'Dilimabaka
- 1 Centre International de Recherches Médicales de Franceville (CIRMF) , Franceville, Gabon
| | - Anais Pinto
- 1 Centre International de Recherches Médicales de Franceville (CIRMF) , Franceville, Gabon
| | | | | | - Jean-Paul Akue
- 1 Centre International de Recherches Médicales de Franceville (CIRMF) , Franceville, Gabon
| | - Eric Maurice Leroy
- 1 Centre International de Recherches Médicales de Franceville (CIRMF) , Franceville, Gabon .,4 UMR 224 (MIVEGEC: Laboratoire Maladies Infectieuses et Vecteurs, Ecologie, Génétique, Evolution et Contrôle), Institut de Recherche pour le Développement (IRD) , IRD/CNRS/UM1/UM2, Montpellier, France
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